public class Text8 {
    // 编辑距离
    public int minDistance (String word1, String word2) {
        // write code here
        int len1 = word1.length();
        int len2 = word2.length();

        if(len1 == 0 ||len2 == 0){
            return len1==0?len2:len1;
        }

        // word1 前i个到 word2 前j个字符的最小距离
        int[][] dp = new int[len1+1][len2+1];

        for(int i = 0; i <= len1; i++){
            dp[i][0] = i;
        }

        for(int i = 0; i <= len2; i++){
            dp[0][i] = i;
        }

        for(int i = 1;i <= len1; i++){
            for(int j = 1;j <= len2; j++){
                if(word1.charAt(i-1) == word2.charAt(j-1)){
                    dp[i][j] = dp[i-1][j-1];
                } else {
                    dp[i][j] = Math.min(Math.min(dp[i-1][j]+1,dp[i][j-1]+1),dp[i-1][j-1]+1);
                }
            }
        }
        return dp[len1][len2];
    }
}
